Use of (2E)-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)pent-2-ene in high temperature heat pumps

ABSTRACT

A method for producing heating in a high temperature heat pump having a heat exchanger is provided. The method comprises extracting heat from a working fluid, thereby producing a cooled working fluid wherein said working fluid comprises (2E)-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)pent-2-ene (“HFO-153-10mzzy”). Also, a high temperature heat pump apparatus is provided containing a working fluid comprising HFO-153-10mzzy. Also a composition is provided comprising (i) a working fluid consisting essentially of HFO-153-10mzzy; and (ii) a stabilizer to prevent degradation at temperatures of 55° C. or above, or (iii) a lubricant suitable for use at 55° C. or above, or both (ii) and (iii).

RELATED APPLICATIONS

This application represents a national filing under 35 U.S.C. 371 ofinternational Application No. PCT/US2015/048234 filed Sep. 3, 2015, andclaims priority to U.S. Provisional Patent Application 62/053,955, filedon Sep. 23, 2014.

BACKGROUND

Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) havebeen employed in a wide range of applications, including their use inhigh temperature heat pumps. CFCs and HCFCs are suspected to contributeto the destruction of stratospheric ozone and to the increase in globalwarming. There is a continued need to seek alternative materialcompositions that do not contribute to the destruction of the ozonelayer and also have a low global warming potential.

SUMMARY

Methods and systems for producing heat in numerous applications, and inparticular, in high temperature heat pumps are provided.

This invention relates to compositions comprising(2E)-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)pent-2-ene)(hereinafter “HFO-153-10mzzy”), as well as methods and systems usingthese compositions in high temperature heat pumps.

(2E)-1,1,1,4,5,5-heptafluoro-4-(trifluoromethyl)pent-2-ene F13iE153-10Mzzy

Embodiments of the present invention involve the compound HFO-153-10mzzyeither alone or in combination with one or more other compounds asdescribed in detail herein below.

In accordance with embodiments of this invention, a method for producingheating in a high temperature heat pump having a heat exchanger. Themethod comprises extracting heat from a working fluid, thereby producinga cooled working fluid wherein said working fluid comprises(2E)-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)pent-2-ene.

Also in accordance with this invention, a method for producing heatingin a high temperature heat pump is provided. The method comprisescondensing a vapor working fluid comprising HFO-153-10mzzy, in acondenser, thereby producing a liquid working fluid.

Also in accordance with this invention, a method of raising the maximumfeasible condenser operating temperature in a high temperature heat pumpapparatus is provided. The method comprises charging the hightemperature heat pump with a working fluid comprising HFO-153-10mzzy.

Also in accordance with this invention, a high temperature heat pumpapparatus is provided. The apparatus contains a working fluid comprisingHFO-153-10mzzy.

Also in accordance with this invention a composition is provided. Thecomposition comprises: (i) a working fluid consisting essentially ofHFO-153-10mzzy; and (ii) a stabilizer to prevent degradation attemperatures of 55° C. or above, or (iii) a lubricant suitable for useat 55° C. or above, or both (ii) and (iii).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of one embodiment of a flooded evaporatorheat pump apparatus which utilizes a composition comprisingHFO-153-10mzzy as working fluid.

FIG. 2 is a schematic diagram of one embodiment of a direct expansionheat pump apparatus which utilizes a composition comprisingHFO-153-10mzzy as working fluid.

FIG. 3 is a schematic diagram of a cascade heat pump system which uses acomposition comprising HFO-153-10mzzy as working fluid.

DETAILED DESCRIPTION

Before addressing details of embodiments described below, some terms aredefined or clarified.

Global warming potential (GWP) is an index for estimating relativeglobal warming contribution due to atmospheric emission of a kilogram ofa particular greenhouse gas compared to emission of a kilogram of carbondioxide. GWP can be calculated for different time horizons showing theeffect of atmospheric lifetime for a given gas. The GWP for the 100 yeartime horizon is commonly the value referenced.

Ozone depletion potential (ODP) is defined in “The Scientific Assessmentof Ozone Depletion, 2002, A report of the World MeteorologicalAssociation's Global Ozone Research and Monitoring Project,” section1.4.4, pages 1.28 to 1.31 (see first paragraph of this section). ODPrepresents the extent of ozone depletion in the stratosphere expectedfrom a compound on a mass-for-mass basis relative tofluorotrichloromethane (CFC-11).

Refrigeration capacity (sometimes referred to as cooling capacity) is aterm to define the change in enthalpy of a refrigerant or working fluidin an evaporator per unit mass of refrigerant or working fluidcirculated. Volumetric cooling capacity refers to the amount of heatremoved by the refrigerant or working fluid in the evaporator per unitvolume of refrigerant vapor exiting the evaporator. The refrigerationcapacity is a measure of the ability of a refrigerant, working fluid orheat transfer composition to produce cooling. Therefore, the higher thevolumetric cooling capacity of the working fluid, the greater thecooling rate that can be produced at the evaporator with the maximumvolumetric flow rate achievable with a given compressor. Cooling raterefers to the heat removed by the refrigerant in the evaporator per unittime.

Similarly, volumetric heating capacity is a term to define the amount ofheat supplied by the refrigerant or working fluid in the condenser perunit volume of refrigerant or working fluid vapor entering thecompressor. The higher the volumetric heating capacity of therefrigerant or working fluid, the greater the heating rate that isproduced at the condenser with the maximum volumetric flow rateachievable with a given compressor.

Coefficient of performance (COP) is the amount of heat removed in theevaporator divided by the energy required to operate the compressor. Thehigher the COP, the higher the energy efficiency. COP is directlyrelated to the energy efficiency ratio (EER), that is, the efficiencyrating for refrigeration or air conditioning equipment at a specific setof internal and external temperatures.

As used herein, a heat transfer medium comprises a composition used tocarry heat from a body to be cooled to a chiller evaporator or from achiller condenser to a cooling tower or other configuration where heatcan be rejected to the ambient.

As used herein, a working fluid comprises a compound or mixture ofcompounds that function to transfer heat in a cycle wherein the workingfluid undergoes a phase change from a liquid to a gas and back to aliquid in a repeating cycle.

Subcooling is the reduction of the temperature of a liquid below thatliquid's saturation point for a given pressure. The saturation point isthe temperature at which a vapor composition is completely condensed toa liquid (also referred to as the bubble point). But subcoolingcontinues to cool the liquid to a lower temperature liquid at the givenpressure. By cooling a liquid below the saturation temperature, the netrefrigeration capacity can be increased. Subcooling thereby improvesrefrigeration capacity and energy efficiency of a system. Subcool amountis the amount of cooling below the saturation temperature (in degrees)or how far below its saturation temperature a liquid composition iscooled.

Superheat is a term that defines how far above the saturation vaportemperature of a vapor composition a vapor composition is heated.Saturation vapor temperature is the temperature at which, if a vaporcomposition is cooled, the first drop of liquid is formed, also referredto as the “dew point”.

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a composition,process, method, article, or apparatus that comprises a list of elementsis not necessarily limited to only those elements but may include otherelements not expressly listed or inherent to such composition, process,method, article, or apparatus. Further, unless expressly stated to thecontrary, “or” refers to an inclusive or and not to an exclusive or. Forexample, a condition A or B is satisfied by any one of the following: Ais true (or present) and B is false (or not present), A is false (or notpresent) and B is true (or present), and both A and B are true (orpresent).

The transitional phrase “consisting of” excludes any element, step, oringredient not specified. If in the claim such would close the claim tothe inclusion of materials other than those recited except forimpurities ordinarily associated therewith. When the phrase “consistsof” appears in a clause of the body of a claim, rather than immediatelyfollowing the preamble, it limits only the element set forth in thatclause; other elements are not excluded from the claim as a whole.

The transitional phrase “consisting essentially of” is used to define acomposition, method or apparatus that includes materials, steps,features, components, or elements, in addition to those literallydisclosed provided that these additional included materials, steps,features, components, or elements do not materially affect the basic andnovel characteristic(s) of the claimed invention. The term ‘consistingessentially of’ occupies a middle ground between “comprising” and‘consisting of’.

Where applicants have defined an invention or a portion thereof with anopen-ended term such as “comprising,” it should be readily understoodthat (unless otherwise stated) the description should be interpreted toalso describe such an invention using the terms “consisting essentiallyof” or “consisting of.”

Also, use of “a” or “an” are employed to describe elements andcomponents described herein. This is done merely for convenience and togive a general sense of the scope of the invention. This descriptionshould be read to include one or at least one and the singular alsoincludes the plural unless it is obvious that it is meant otherwise.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although methods and materialssimilar or equivalent to those described herein can be used in thepractice or testing of embodiments of the present invention, suitablemethods and materials are described below. All publications, patentapplications, patents, and other references mentioned herein areincorporated by reference in their entirety, unless a particular passageis cited. In case of conflict, the present specification, includingdefinitions, will control. In addition, the materials, methods, andexamples are illustrative only and not intended to be limiting.

(2E)-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)pent-2-ene)(“HFO-153-10mzzy), can be prepared by dehydroiodination of1,1,1,2,5,5,5-heptafluoro-2-(trifluoromethyl)-4-iodopentane as disclosedin U.S. Pat. No. 8,148,584, incorporated herein by reference.

High Temperature Heat Pump Methods

In accordance with this invention, a method for producing heating in ahigh temperature heat pump having a heat exchanger. The method comprisesextracting heat from a working fluid, thereby producing a cooled workingfluid wherein said working fluid comprises HFO-153-10mzzy.

In one embodiment, the heat exchanger is a supercritical working fluidcooler or just working fluid cooler. In another embodiment, the heatexchanger is a condenser.

In one embodiment is provided a method for producing heating in a hightemperature heat pump comprising condensing a vapor working fluidcomprising HFO-153-10mzzy, in a condenser, thereby producing a liquidworking fluid. Of note are methods wherein a vapor working fluidconsisting essentially of HFO-153-10mzzy is condensed.

Of particular utility in high temperature heat pumps are compositionscomprising HFO-153-10mzzy. HFO-153-10mzzy meets the need for anon-flammable high temperature heat pump working fluid with reduced GWP.

Some high temperature heat pumps operated with HFO-153-10mzzy as theworking fluid have vapor pressures below the threshold necessitatingcompliance with provisions of the ASME Boiler and Pressure Vessel Code.Such compositions are desirable for use in high temperature heat pumps.Of note are compositions where the working fluid consists essentially offrom about 1 to about 100 weight percent HFO-153-10mzzy.

In one embodiment, the method for producing heating in a heat pumphaving a condenser or working fluid cooler, further comprises passing aheat transfer medium through the condenser or working fluid cooler,whereby cooling (and sometimes condensation) of the working fluid heatsthe heat transfer medium, and passing the heated heat transfer mediumfrom the condenser or working fluid cooler to a body to be heated.

A body to be heated may be any space, object or fluid that may beheated. In one embodiment, a body to be heated may be a room, building,or the passenger compartment of an automobile. Alternatively, in anotherembodiment, a body to be heated may be a secondary loop fluid, heattransfer medium or heat transfer fluid.

In one embodiment, the heat transfer medium is water and the body to beheated is water. In another embodiment, the heat transfer medium iswater and the body to be heated is air for space heating. In anotherembodiment, the heat transfer medium is an industrial heat transferliquid and the body to be heated is a chemical process stream.

In another embodiment, the method to produce heating further comprisescompressing the working fluid vapor in a dynamic (e.g. axial orcentrifugal) compressor or in a positive displacement (e.g.reciprocating, screw or scroll) compressor.

In one embodiment, the method for producing heating in a heat pumphaving a condenser, further comprises passing a fluid to be heatedthrough the condenser, thus heating the fluid. In one embodiment, thefluid is air, and the heated air from the condenser is passed to a spaceto be heated. In another embodiment, the fluid is a portion of a processstream, and the heated portion is returned to the process.

In certain embodiments, the heat transfer medium is selected from wateror glycol. The glycol can be, for example, ethylene glycol or propyleneglycol. Of particular note is an embodiment wherein the heat transfermedium is water and the body to be heated is air for space heating.

In another embodiment, the heat transfer medium is an industrial heattransfer liquid, and the body to be heated is a chemical process stream,which, as used herein, chemical process stream includes process linesand process equipment such as distillation columns. Of note areindustrial heat transfer liquids including ionic liquids, various brinessuch as aqueous calcium chloride or sodium chloride, glycols such aspropylene glycol or ethylene glycol, methanol, and other heat transfermedia such as those listed in section 4 of the 2006 ASHRAE Handbook onRefrigeration.

In one embodiment, the method for producing heating comprises extractingheat in a flooded evaporator high temperature heat pump as describedabove with respect to FIG. 1, discussed in more detail herein below. Inthis method, the liquid working fluid is evaporated to form a workingfluid vapor in the vicinity of a first heat transfer medium. The firstheat transfer medium is a warm liquid, such as water, which istransported into the evaporator via a pipe from a low temperature heatsource. The warm liquid is cooled and is returned to the low temperatureheat source or is passed to a body to be cooled, such as a building. Theworking fluid vapor is then condensed in the vicinity of a second heattransfer medium, which is a chilled liquid which is brought in from thevicinity of a body to be heated (heat sink). The second heat transfermedium cools the working fluid such that it is condensed to form aliquid working fluid. In this method a flooded evaporator heat pump mayalso be used to heat domestic or service water or a process stream.

In another embodiment, the method for producing heating comprisesproducing heating in a direct expansion high temperature heat pump asdescribed above with respect to FIG. 2, discussed in more detail hereinbelow. In this method, working fluid liquid is passed through anevaporator and evaporates to produce a working fluid vapor. A firstliquid heat transfer medium is cooled by the evaporating working fluid.The first liquid heat transfer medium is passed out of the evaporator toa low temperature heat source or a body to be cooled. The working fluidvapor is then condensed or cooled in the vicinity of a second heattransfer medium, which is a chilled liquid which is brought in from thevicinity of a body to be heated (heat sink). The second heat transfermedium cools the working fluid such that it is condensed to form aliquid working fluid. In this method, a direct expansion heat pump mayalso be used to heat domestic or service water or a process stream.

In one embodiment of the method for producing heating, the hightemperature heat pump includes a compressor which is a centrifugalcompressor.

In another embodiment of the invention a method is provided for raisingthe maximum feasible condenser operating temperature in a hightemperature heat pump apparatus comprising charging the high temperatureheat pump with a working fluid comprising HFO-153-10mzzy.

The critical temperature and pressure of HFO-153-10mzzy are 170.24° C.and 2.04 MPa (296.2 psia), respectively. The boiling point ofHFO-153-10mzzy is 49° C. Compositions comprising HFO-153-10mzzy can havelower vapor pressures and higher critical temperatures than workingfluids commonly used in high temperature heat pumps today, such asHFC-245fa. Use of a composition comprising HFO-153-10mzzy in a hightemperature heat pump originally designed for a working fluid with ahigher vapor pressure and a lower critical temperature than the saidcomposition comprising HFO-153-10mzzy can allow operation of the hightemperature heat pump at condenser temperatures higher than achievablewith the working fluid for which the high temperature heat pump wasoriginally designed. For example, the condenser temperature of acentrifugal heat pump with a maximum design working pressure of 2.18 MPaoperating with HFC-245fa as the working fluid cannot exceed 126.2° C.Regardless of limitations on the maximum permissible working pressure,the maximum condenser temperature with HFC-245fa cannot exceed itscritical temperature of about 154° C. However, the condenser temperatureof a centrifugal heat pump with a maximum design working pressure of2.18 MPa operating with HFO-153-10mzzy as the working fluid can reachtemperatures approaching the critical temperature of HFO-15310mzzy of170.24° C. without exceeding the maximum permissible design workingpressure.

When HFO-153-10mzzy is used as the working fluid in a high temperatureheat pump, the maximum feasible condenser operating temperature is about160-170° C. In one embodiment of the method to raise the maximumfeasible condenser operating temperature, when a composition comprisingHFO-153-10mzzy, is used as the heat pump working fluid, the maximumfeasible condenser operating temperature is raised to a temperatureequal to or greater than about 165° C.

It is feasible that heating temperatures as high as 200-250° C. areachievable with a high temperature heat pump utilizing HFO-153-10mzzy.However at heating temperatures above about 165° C., some modificationof equipment or materials, may be necessary to accommodate the higherpressures associated with these higher temperatures and to extract heatfrom the working fluid at temperatures above its critical temperaturewithout condensation (i.e. in a transcritical mode of operation).

In accordance with this invention it is possible to replace a hightemperature heat pump fluid (for example, HFC-245fa) in a systemoriginally designed for said high temperature heat pump fluid with aworking fluid comprising HFO-153-10mzzy in order to raise the condenseroperating temperature.

A composition comprising HFO-153-10mzzy enables the design and operationof dynamic (e.g. centrifugal) or positive displacement (e.g. screw orscroll) heat pumps for upgrading heat available at low temperatures tomeet demands for heating at higher temperatures. The available lowtemperature heat is supplied to the evaporator and the high temperatureheat is extracted at the condenser or working fluid cooler (in asupercritical or transcritical mode). For example, waste heat can beavailable to be supplied to the evaporator of a heat pump operating at25° C. at a location (e.g. a hospital) where heat from the condenser,operating at 85° C., can be used to heat water (e.g. for hydronic spaceheating or other service).

In some cases heat may be available from various other sources (e.g.waste heat from process streams, geothermal heat or solar heat) attemperatures higher than suggested above, while heating at even highertemperatures may be required. For example, waste heat may be availableat 100° C. while heating at 130° C. may be required for an industrialapplication. The lower temperature heat can be supplied to theevaporator of a dynamic (e.g. centrifugal) or positive displacement heatpump in the method or system of this invention to be uplifted to thedesired temperature of 130° C. and be delivered at the condenser. Inanother example, waste heat can be available to be supplied to theevaporator of a heat pump operating with HFO-153-10mzzy as the workingfluid at 130° C. at a location (e.g. an industrial operation) where heatfrom the condenser, operating at 165° C., can be used to heat a processstream.

High Temperature Heat Pump Apparatus

In one embodiment of the present invention is provided a heat pumpapparatus containing a working fluid comprising HFO-153-10mzzy. Of noteare embodiments wherein the working fluid consists essentially ofHFO-153-10mzzy.

A heat pump is a type of apparatus for producing heating and/or cooling.A heat pump includes an evaporator, a compressor, a condenser or workingfluid cooler, and an expansion device. A working fluid circulatesthrough these components in a repeating cycle. Heating is produced atthe condenser or working fluid cooler where energy (in the form of heat)is extracted from the vapor (or supercritical fluid) working fluid as itis condensed (or cooled) to form liquid working fluid. Cooling isproduced at the evaporator where energy is absorbed to evaporate theworking fluid to form vapor working fluid.

In one embodiment, the heat pump apparatus comprises an evaporator, acompressor, a condenser (or working fluid cooler) and a pressurereduction device, all of which are in fluid communication in the orderlisted and through which a working fluid flows from one component to thenext in a repeating cycle.

In one embodiment the heat pump apparatus comprises (a) an evaporatorthrough which a working fluid flows and is evaporated; (b) a compressorin fluid communication with the evaporator that compresses theevaporated working fluid to a higher pressure; (c) a condenser in fluidcommunication with the compressor through which the high pressureworking fluid vapor flows and is condensed; and (d) a pressure reductiondevice in fluid communication with the condenser wherein the pressure ofthe condensed working fluid is reduced and said pressure reductiondevice further being in fluid communication with the evaporator suchthat the working fluid may repeat flow through components (a), (b), (c)and (d) in a repeating cycle; wherein the working fluid comprisesHFO-153-10mzzy.

Heat pumps for use in this invention include flooded evaporators, oneembodiment of which is shown in FIG. 1, and direct expansionevaporators, one embodiment of which is shown in FIG. 2.

Heat pumps may utilize positive displacement compressors or dynamiccompressors (e.g. centrifugal compressors or axial compressors).Positive displacement compressors include reciprocating, screw, orscroll compressors. Of note are heat pumps that use screw compressors.Also of note are heat pumps that use centrifugal compressors.

Residential heat pumps are used to produce heated air to warm aresidence or home (including single family or multi-unit attached homes)and produce maximum condenser operating temperatures from about 30° C.to about 50° C.

Of note are high temperature heat pumps that may be used to heat air,water, another heat transfer medium or some portion of an industrialprocess, such as a piece of equipment, storage area or process stream.These high temperature heat pumps can produce maximum condenseroperating temperatures greater than about 55° C. The maximum condenseroperating temperature that can be achieved in a high temperature heatpump depends on the working fluid used. This maximum condenser operatingtemperature is limited by the normal boiling characteristics of theworking fluid and also by the pressure to which the heat pump'scompressor can raise the vapor working fluid pressure. This maximumpressure is also related to the working fluid used in the heat pump.

Of particular value are high temperature heat pumps that operate atcondenser temperatures of at least about 75° C. Also of note are hightemperature heat pumps that operate at condenser temperatures of atleast about 100° C. Also of note high temperature heat pumps thatoperate at condenser temperatures of at least about 125° C. Compositionscomprising HFO-153-10mzzy enable the design and operation of centrifugalheat pumps, operated at condenser temperatures higher than thoseaccessible with many currently available working fluids. Of note areembodiments using working fluids comprising HFO-153-10mzzy operated atcondenser temperatures up to about 160 to 169° C.

Also of note are heat pumps that are used to produce heating and coolingsimultaneously. For instance, a single heat pump unit may produce hotwater for domestic use and may also produce cooling for comfort airconditioning in the summer.

Heat pumps, including both flooded evaporator and direct expansion, maybe coupled with an air handling and distribution system to providecomfort air conditioning (cooling and dehumidifying the air) and/orheating to residence (single family or attached homes) and largecommercial buildings, including hotels, office buildings, hospitals,schools, universities, and the like. In another embodiment, heat pumpsmay be used to heat water.

To illustrate how heat pumps operate, reference is made to the Figures.One embodiment of a flooded evaporator heat pump is shown in FIG. 1. Inthis heat pump a first heat transfer medium, which is a warm liquid,which comprises water, and, in some embodiments, additives, or otherheat transfer medium such as a glycol (e.g., ethylene glycol orpropylene glycol), enters the heat pump carrying heat from a lowtemperature source (not shown), such as a building air handling systemor warmed-up water from condensers of a chiller plant flowing to acooling tower, shown entering the heat pump at arrow 3, through a tubebundle or coil 9, in an evaporator 6, which has an inlet and an outlet.The warm first heat transfer medium is delivered to evaporator 6, whereit is cooled by liquid working fluid, which is shown in the lowerportion of evaporator 6. The liquid working fluid evaporates at a lowertemperature than the warm first heat transfer medium which flows throughtube bundle or coil 9. The cooled first heat transfer mediumre-circulates back to the low temperature heat source as shown by arrow4, via a return portion of tube bundle or coil 9. The liquid workingfluid, shown in the lower portion of evaporator 6, vaporizes and isdrawn into compressor 7, which increases the pressure and temperature ofthe working fluid vapor. Compressor 7 compresses this vapor so that itmay be condensed in condenser 5 at a higher pressure and temperaturethan the pressure and temperature of the working fluid vapor when itexits evaporator 6. A second heat transfer medium enters the condenservia a tube bundle or coil 10 in condenser 5 from a location where hightemperature heat is provided (“heat sink”) such as a domestic or servicewater heater or a hydronic heating system at arrow 1. The second heattransfer medium is warmed in the process and returned via a return loopof tube bundle or coil 10 and arrow 2 to the heat sink. This second heattransfer medium cools the working fluid vapor in condenser 5 and causesthe vapor to condense to liquid working fluid, so that there is liquidworking fluid in the lower portion of condenser 5. Condensed liquidworking fluid in condenser 5 flows back to evaporator 6 throughexpansion device 8, which may be an orifice, capillary tube or expansionvalve. Expansion device 8 reduces the pressure of the liquid workingfluid, and converts the liquid working fluid partially to vapor, that isto say that the liquid working fluid flashes as pressure drops betweencondenser 5 and evaporator 6. Flashing cools the working fluid, i.e.,both the liquid working fluid and the working fluid vapor to thesaturated temperature at evaporator pressure, so that both liquidworking fluid and working fluid vapor are present in evaporator 6.

In some embodiments the working fluid vapor is compressed to asupercritical state and condenser 5 is replaced by a gas cooler wherethe working fluid vapor is cooled to a liquid state withoutcondensation.

In some embodiments the first heat transfer medium used in the apparatusdepicted in FIG. 1 is chilled water returning from a building where airconditioning is provided or from some other body to be cooled. Heat isextracted from the returning chilled water at evaporator 6 and thecooled chilled water is supplied back to the building or other body tobe cooled. In this embodiment the apparatus depicted in FIG. 1 functionsto simultaneously cool the first heat transfer medium that providescooling to a body to be cooled (e.g. building air) and heat the secondheat transfer medium that provides heating to a body to be heated (e.g.domestic or service water or process stream).

It is understood that the apparatus depicted in FIG. 1 can extract heatat evaporator 6 from a wide variety of heat sources including solar,geothermal and waste heat and supply heat from condenser 5 to a widerange of heat sinks.

It should be noted that for a single component working fluidcomposition, the composition of the vapor working fluid in theevaporator and condenser is the same as the composition of the liquidworking fluid in the evaporator and condenser. In this case, evaporationwill occur at a constant temperature. However, if a working fluid blend(or mixture) is used, as in the present invention, the liquid workingfluid and the working fluid vapor in the evaporator (or in thecondenser) may have different compositions. This may lead to inefficientsystems and difficulties in servicing the equipment, thus a singlecomponent working fluid is more desirable. An azeotrope orazeotrope-like composition will function essentially as a singlecomponent working fluid in a heat pump, such that the liquid compositionand the vapor composition are essentially the same reducing anyinefficiency that might arise from the use of a non-azeotropic ornon-azeotrope-like composition.

One embodiment of a direct expansion heat pump is illustrated in FIG. 2.In the heat pump as illustrated in FIG. 2, first liquid heat transfermedium, which is a warm liquid, such as warm water, enters evaporator 6′at inlet 14. Mostly liquid working fluid (with a small amount of workingfluid vapor) enters coil 9′ in the evaporator at arrow 3′ andevaporates. As a result, first liquid heating medium is cooled inevaporator 6′, and a cooled first liquid heating medium exits evaporator6′ at outlet 16, and is sent to low temperature heat source (e.g. warmwater flowing to a cooling tower). The working fluid vapor exitsevaporator 6′ at arrow 4′ and is sent to compressor 7′, where it iscompressed and exits as high temperature, high pressure working fluidvapor. This working fluid vapor enters condenser 5′ through condensercoil 10′ at 1′. The working fluid vapor is cooled by a second liquidheating medium, such as water, in condenser 5′ and becomes a liquid. Thesecond liquid heating medium enters condenser 5′ through condenser heattransfer medium inlet 20. The second liquid heating medium extracts heatfrom the condensing working fluid vapor, which becomes liquid workingfluid, and this warms the second liquid heating medium in condenser 5′.The second liquid heating medium exits from condenser 5′ throughcondenser heat transfer medium outlet 18. The condensed working fluidexits condenser 5′ through lower coil 10′ and flows through expansiondevice 12, which may be an orifice, capillary tube or expansion valve.Expansion device 12 reduces the pressure of the liquid working fluid. Asmall amount of vapor, produced as a result of the expansion, entersevaporator 6′ with liquid working fluid through coil 9′ and the cyclerepeats.

In some embodiments the working fluid vapor is compressed to asupercritical state and condenser 5′ is replaced by a gas cooler wherethe working fluid vapor is cooled to a liquid state withoutcondensation.

In some embodiments the first heat transfer medium used in the apparatusdepicted in FIG. 2 is chilled water returning from a building where airconditioning is provided or from some other body to be cooled. Heat isextracted from the returning chilled water at the evaporator 6′ and thecooled chilled water is supplied back to the building or other body tobe cooled. In this embodiment the apparatus depicted in FIG. 2 functionsto simultaneously cool the first heat transfer medium that providescooling to a body to be cooled (e.g. building air) and heat the secondheat transfer medium that provides heating to a body to be heated (e.g.domestic or service water or process stream).

It is understood that the apparatus depicted in FIG. 2 can extract heatat the evaporator 6′ from a wide variety of heat sources includingsolar, geothermal and waste heat and supply heat from the condenser 5′to a wide range of heat sinks.

Compressors useful in the present invention include dynamic compressors.Of note as examples of dynamic compressors are centrifugal compressors.A centrifugal compressor uses rotating elements to accelerate theworking fluid radially, and typically includes an impeller and diffuserhoused in a casing. Centrifugal compressors usually take working fluidin at an impeller eye, or central inlet of a circulating impeller, andaccelerate it radially outward through passages. Some static pressurerise occurs in the impeller, but most of the pressure rise occurs in thediffuser section of the casing, where velocity is converted to staticpressure. Each impeller-diffuser set is a stage of the compressor.Centrifugal compressors are built with from 1 to 12 or more stages,depending on the final pressure desired and the volume of refrigerant tobe handled.

The pressure ratio, or compression ratio, of a compressor is the ratioof absolute discharge pressure to the absolute inlet pressure. Pressuredelivered by a centrifugal compressor is practically constant over arelatively wide range of capacities. The pressure a centrifugalcompressor can develop depends on the tip speed of the impeller. Tipspeed is the speed of the impeller measured at its tip and is related tothe diameter of the impeller and its revolutions per minute. The tipspeed required in a specific application depends on the compressor workthat is required to elevate the thermodynamic state of the working fluidfrom evaporator to condenser conditions. Volumetric flow capacity of acentrifugal compressor is determined by the size of the passages throughthe impeller. This makes the size of the compressor more dependent onthe pressure required than the volumetric flow capacity required.

Also of note as examples of dynamic compressors are axial compressors. Acompressor in which the fluid enters and leaves in the axial directionis called an axial flow compressor. Axial compressors are rotating,airfoil- or blade-based compressors in which a working fluid principallyflows parallel to the axis of rotation. This is in contrast with otherrotating compressors such as centrifugal or mixed-flow compressors inwhich a working fluid may enter axially but will have a significantradial component on exit. Axial flow compressors produce a continuousflow of compressed gas, and have the benefits of high efficiencies andlarge mass flow capacity, particularly in relation to theircross-section. They do, however, require several rows of airfoils toachieve large pressure rises making them complex and expensive relativeto other designs.

Compressors useful in the present invention also include positivedisplacement compressors. Positive displacement compressors draw vaporinto a chamber, and the chamber decreases in volume to compress thevapor. After being compressed, the vapor is forced from the chamber byfurther decreasing the volume of the chamber to zero or nearly zero.

Of note as examples of positive displacement compressors arereciprocating compressors. Reciprocating compressors use pistons drivenby a crankshaft. They can be either stationary or portable, can besingle or multi-staged, and can be driven by electric motors or internalcombustion engines. Small reciprocating compressors from 5 to 30 hp areseen in automotive applications and are typically for intermittent duty.Larger reciprocating compressors up to 100 hp are found in largeindustrial applications. Discharge pressures can range from low pressureto very high pressure (above 5000 psi or 35 MPa).

Also of note as examples of positive displacement compressors are screwcompressors. Screw compressors use two meshed rotatingpositive-displacement helical screws to force the gas into a smallerspace. Screw compressors are usually for continuous operation incommercial and industrial application and may be either stationary orportable. Their application can be from 5 hp (3.7 kW) to over 500 hp(375 kW) and from low pressure to very high pressure (above 1200 psi or8.3 MPa).

Also of note as examples of positive displacement compressors are scrollcompressors. Scroll compressors are similar to screw compressors andinclude two interleaved spiral-shaped scrolls to compress the gas. Theoutput is more pulsed than that of a rotary screw compressor.

In one embodiment, the high temperature heat pump apparatus of thepresent invention has at least two heating stages arranged as a cascadeheating system, wherein each stage is in thermal communication with thenext stage and wherein each stage circulates a working fluidtherethrough, wherein heat is transferred to the final stage from theimmediately preceding stage and wherein the heating fluid of the finalstage comprises HFO-153-10mzzy.

In some embodiments, the high temperature heat pump apparatus of thepresent invention has at least two heating stages arranged as a cascadeheating system, each stage being in thermal communication and the nextstage circulating a working fluid therethrough, wherein said apparatuscomprises (a) a first expansion device for reducing the pressure andtemperature of a first working fluid liquid; (b) an evaporator in fluidcommunication with the first expansion device having an inlet and anoutlet. The first working fluid liquid from the first expansion deviceenters the evaporator through the evaporator inlet and is evaporated inthe evaporator to form a first working fluid vapor, and circulates tothe evaporator outlet. The apparatus further comprises (c) a firstcompressor in fluid communication with the evaporator having an inletand an outlet. The first working fluid vapor from the evaporator outletcirculates to the inlet of the first compressor and is compressed,thereby increasing the pressure and the temperature of the first workingfluid vapor, and the compressed first refrigerant vapor circulates tothe outlet of the first compressor. The apparatus further comprises (d)a cascade heat exchanger system in fluid communication with the firstcompressor outlet having: (i) a first inlet and a first outlet, and (ii)a second inlet and a second outlet in thermal communication with thefirst inlet and outlet. The first working fluid vapor from the firstcompressor circulates from the first inlet to the first outlet and iscondensed in the heat exchanger system to form a first working fluidliquid, thereby rejecting heat. A second working fluid liquid circulatesfrom the second inlet to the second outlet and absorbs the heat rejectedby the first working fluid and forms a second working fluid vapor. Theapparatus further comprises (e) a second compressor in fluidcommunication with the second outlet of the cascade heat exchangersystem, said second compressor having an inlet and an outlet. The secondworking fluid vapor from the cascade heat exchanger system second outletis drawn into the compressor and is compressed, thereby increasing thepressure and temperature of the second working fluid vapor. Theapparatus further comprises (f) a condenser in fluid communication withthe second compressor having an inlet and an outlet for circulating thesecond working fluid vapor therethrough and for condensing the secondworking fluid vapor from the compressor to form a second working fluidliquid, thereby producing heat. The second working fluid liquid exitsthe condenser through the outlet. The apparatus further comprises (g) asecond expansion device in fluid communication with the condenser forreducing the pressure and temperature of the second working fluid liquidexiting the condenser and entering the second inlet of the cascade heatexchanger system. The second working fluid comprises HFO-153-10mzzy.

In one embodiment, the high temperature heat pump apparatus may comprisemore than one heating circuit (or loop). The performance (coefficient ofperformance for heating and volumetric heating capacity) of hightemperature heat pumps operated with HFO-153-10mzzy as the working fluidis drastically improved when the evaporator is operated at temperaturesapproaching the condenser temperature required by the application. Whenthe heat supplied to the evaporator is only available at lowtemperatures, thus requiring high temperature lifts leading to poorperformance, a dual fluid/dual circuit cascade cycle configuration isadvantageous. The low stage or low temperature circuit of the cascadecycle is operated with a fluid of lower boiling point thanHFO-153-10mzzy and preferably with a low GWP, including HFO-1234yf(2,3,3,3-tetrafluoropropene), HFO-1234ze-E(E-1,3,3,3-tetrafluoropropene), HFO-1234ye (1,2,3,3-tetrafluoropropene),HFO-1243zf (3,3,3-trifluoropropene), HFC-32 (difluoromethane), HFC-125(pentafluoroethane), HFC-134a (1,1,1,2-tetrafluoroethane), HFC-134(1,1,2,2-tetrafluoroethane), HFC-143a (1,1,1-trifluoroethane), HFC-152a(1,1-difluoroethane), HFC-227ea (1,1,1,2,3,3,3-heptafluoropropane) andtheir blends such as HFO-1234yf/HFC-32, HFO-1234yf/HFC-32/HFC-125,HFO-1234yf/HFC-134a, HFO-1234yf/HFC-134a/HFC-32, HFO-1234yf/HFC-134,HFO-1234yf/HFC-134a/HFC-134, HFO-1234yf/HFC-32/HFC-125/HFC-134a,HFO-1234ze-E/HFC-134a, HFO-1234ze-E/HFC-134,HFO-1234ze-E/HFC-134a/HFC-134, HFO-1234ze-E/HFC-227ea,HFO-1234ze-E/HFC-134/HFC-227ea, HFO-1234ze-E/HFC-134/HFC-134a/HFC-227ea,HFO-1234yf/HFO-1234ze-E/HFC-134/HFC-134a/HFC-227ea, etc. The evaporatorof the low temperature circuit (or low temperature loop) of the cascadecycle receives the available low temperature heat, lifts the heat to atemperature intermediate between the temperature of the available lowtemperature heat and the temperature of the required heating duty andtransfers the heat to the high stage or high temperature circuit (orhigh temperature loop) of the cascade system at a cascade heatexchanger. Then the high temperature circuit, operated withHFO-153-10mzzy, further lifts the heat received at the cascade heatexchanger to the required condenser temperature to meet the intendedheating duty. The cascade concept may be extended to configurations withthree or more circuits lifting heat over wider temperature ranges andusing different fluids over different temperature sub-ranges to optimizeperformance.

In one embodiment of the high temperature heat pump apparatus havingmore than one stage, the first working fluid comprises at least onefluoroolefin selected from the group consisting of HFO-1234yf,E-HFO-1234ze, HFO-1234ye (E- or Z-isomer), and HFC-1243zf.

In another embodiment of the high temperature heat pump apparatus havingmore than one stage, the first working fluid comprises at least onefluoroalkane selected from the group consisting of HFC-32, HFC-125,HFC-134a, HFC-134, HFC-143a, HFC-152a and HFC-227ea.

In another embodiment of the high temperature heat pump apparatus havingmore than one stage, the working fluid of the stage preceding the finalstage comprises at least one fluoroolefin selected from the groupconsisting of HFO-1234yf, E-HFO-1234ze, HFO-1234ye (E- or Z-isomer), andHFC-1243zf.

In another embodiment of the high temperature heat pump apparatus havingmore than one stage, wherein the working fluid of the stage precedingthe final stage comprises at least one fluoroalkane selected from thegroup consisting of HFC-32, HFC-125, HFC-134a, HFC-134, HFC-143a,HFC-152a and HFC-227ea.

In accordance with the present invention, there is provided a cascadeheat pump system having at least two heating loops for circulating aworking fluid through each loop. One embodiment of such a cascade systemis shown generally at 110 in FIG. 3. Cascade heat pump system 110 of thepresent invention has at least two heating loops, including a first, orlower loop 112, which is a low temperature loop, and a second, or upperloop 114, which is a high temperature loop 114. Each circulates aworking fluid therethrough.

Cascade heat pump system 110 includes first expansion device 116. Firstexpansion device 116 has an inlet 116 a and an outlet 116 b. Firstexpansion device 116 reduces the pressure and temperature of a firstworking fluid liquid which circulates through the first or lowtemperature loop 112.

Cascade heat pump system 110 also includes evaporator 118. Evaporator118 has an inlet 118 a and an outlet 118 b. The first working fluidliquid from first expansion device 116 enters evaporator 118 throughevaporator inlet 118 a and is evaporated in evaporator 118 to form afirst working fluid vapor. The first working fluid vapor then circulatesto evaporator outlet 118 b.

Cascade heat pump system 110 also includes first compressor 120. Firstcompressor 120 has an inlet 120 a and an outlet 120 b. The first workingfluid vapor from evaporator 118 circulates to inlet 120 a of firstcompressor 120 and is compressed, thereby increasing the pressure andthe temperature of the first working fluid vapor. The compressed firstworking fluid vapor then circulates to the outlet 120 b of the firstcompressor 120.

Cascade heat pump system 110 also includes cascade heat exchanger system122. Cascade heat exchanger 122 has a first inlet 122 a and a firstoutlet 122 b. The first working fluid vapor from first compressor 120enters first inlet 122 a of heat exchanger 122 and is condensed in heatexchanger 122 to form a first working fluid liquid, thereby rejectingheat. The first working fluid liquid then circulates to first outlet 122b of heat exchanger 122. Heat exchanger 122 also includes a second inlet122 c and a second outlet 122 d. A second working fluid liquidcirculates from second inlet 122 c to second outlet 122 d of heatexchanger 122 and is evaporated to form a second working fluid vapor,thereby absorbing the heat rejected by the first working fluid (as it iscondensed). The second working fluid vapor then circulates to secondoutlet 122 d of heat exchanger 122. Thus, in the embodiment of FIG. 3,the heat rejected by the first working fluid is directly absorbed by thesecond working fluid.

Cascade heat pump system 110 also includes second compressor 124. Secondcompressor 124 has an inlet 124 a and an outlet 124 b. The secondworking fluid vapor from cascade heat exchanger 122 is drawn intocompressor 124 through inlet 124 a and is compressed, thereby increasingthe pressure and temperature of the second working fluid vapor. Thesecond working fluid vapor then circulates to outlet 124 b of secondcompressor 124.

Cascade heat pump system 110 also includes condenser 126 having an inlet126 a and an outlet 126 b. The second working fluid from secondcompressor 124 circulates from inlet 126 a and is condensed in condenser126 to form a second working fluid liquid, thus producing heat. Thesecond working fluid liquid exits condenser 126 through outlet 126 b.

Cascade heat pump system 110 also includes second expansion device 128having an inlet 128 a and an outlet 128 b. The second working fluidliquid passes through second expansion device 128, which reduces thepressure and temperature of the second working fluid liquid exitingcondenser 126. This liquid may be partially vaporized during thisexpansion. The reduced pressure and temperature second working fluidliquid circulates to second inlet 122 c of cascade heat exchanger system122 from expansion device 128.

Moreover, in the event that HFO-153-10mzzy is stable at temperatureshigher than the critical temperature, then these working fluids enabledesign of heat pumps operated according to a supercritical and/ortranscritical cycle in which heat is rejected by the working fluid in asupercritical state and made available for use over a range oftemperatures (including temperatures higher that the criticaltemperature of HFO-153-10mzzy). The supercritical fluid is cooled to aliquid state without passing through an isothermal condensationtransition.

For high temperature condenser operation (associated with hightemperature lifts and high compressor discharge temperatures)formulations of working fluid (e.g. HFO-153-10mzzy) and lubricants withhigh thermal stability (possibly in combination with oil cooling orother mitigation approaches) will be advantageous.

For high temperature condenser operation (associated with hightemperature lifts and high compressor discharge temperatures) use ofmagnetic centrifugal compressors (e.g. Danfoss-Turbocor type) that donot require the use of lubricants will be advantageous.

For high temperature condenser operation (associated with hightemperature lifts and high compressor discharge temperatures) use ofcompressor materials (e.g. shaft seals, etc) with high thermal stabilitymay also be required.

The composition comprising HFO-153-10mzzy may be used in a hightemperature heat pump apparatus in combination with molecular sieves toaid in removal of moisture. Desiccants may comprise activated alumina,silica gel, or zeolite-based molecular sieves. In certain embodiments,the preferred molecular sieves have a pore size of approximately 3Angstroms, 4 Angstroms, or 5 Angstroms. Representative molecular sievesinclude MOLSIV XH-7, XH-6, XH-9 and XH-11 (UOP LLC, Des Plaines, Ill.).

High Temperature Heat Pump Compositions

A composition is provided for use in high temperature heat pumps. Thecomposition comprises: (i) a working fluid consisting essentially ofHFO-153-10mzzy and (ii) a stabilizer to prevent degradation attemperatures of 55° C. or above, or (iii) a lubricant suitable for useat 55° C. or above, or both (ii) and (iii). Of note are compositionswherein the working fluid component consists essentially ofHFO-153-10mzzy.

High temperature heat pumps operated with HFO-153-10mzzy can have vaporpressures below the threshold (15 psig) necessitating compliance withprovisions of the ASME Boiler and Pressure Vessel Code. Suchcompositions are desirable for use in high temperature heat pumps.

Further, in another embodiment, low GWP compositions are desirable. Ofnote are compositions comprising at least 1-100 weight ofHFO-153-10mzzy, which have GWP values lower than 1500, preferably lowerthan 1000, more preferably lower than 750, more preferably lower than500, more preferably lower than 150 and even more preferably lower than10. The compositions of the present invention can be prepared by anyconvenient method including mixing or combining the desired amounts. Inone embodiment of this invention, a composition can be prepared byweighing the desired component amounts and thereafter combining them inan appropriate vessel.

The composition comprising HFO-153-10mzzy may also comprise and/or beused in combination with at least one lubricant selected from the groupconsisting of polyalkylene glycols, polyol esters, polyvinylethers,mineral oils, alkylbenzenes, synthetic paraffins, synthetic naphthenes,and poly(alpha)olefins.

Useful lubricants include those suitable for use with high temperatureheat pump apparatus. Among these lubricants are those conventionallyused in vapor compression refrigeration apparatus utilizingchlorofluorocarbon refrigerants. In one embodiment, lubricants comprisethose lubricants commonly known as “mineral oils” in the field ofcompression refrigeration lubrication. Mineral oils comprise paraffins(i.e., straight-chain and branched-carbon-chain, saturatedhydrocarbons), naphthenes (i.e. cyclic paraffins) and aromatics (i.e.unsaturated, cyclic hydrocarbons containing one or more ringscharacterized by alternating double bonds). In one embodiment,lubricants comprise those commonly known as “synthetic oils” in thefield of compression refrigeration lubrication. Synthetic oils comprisealkylaryls (i.e. linear and branched alkyl alkylbenzenes), syntheticparaffins and naphthenes, and poly(alphaolefins). Representativeconventional lubricants are the commercially available BVM 100 N(paraffinic mineral oil sold by BVA Oils), naphthenic mineral oilcommercially available from Crompton Co. under the trademarks Suniso®3GS and Suniso® 5GS, naphthenic mineral oil commercially available fromPennzoil under the trademark Sontex® 372LT, naphthenic mineral oilcommercially available from Calumet Lubricants under the trademarkCalumet® RO-30, linear alkylbenzenes commercially available from ShrieveChemicals under the trademarks Zerol® 75, Zerol® 150 and Zerol® 500, andHAB 22 (branched alkylbenzene sold by Nippon Oil).

Useful lubricants may also include those which have been designed foruse with hydrofluorocarbon refrigerants and are miscible withrefrigerants of the present invention under compression refrigerationand air-conditioning apparatus' operating conditions. Such lubricantsinclude, but are not limited to, polyol esters (POEs) such as Castrol®100 (Castrol, United Kingdom), polyalkylene glycols (PAGs) such asRL-488A from Dow (Dow Chemical, Midland, Mich.), polyvinyl ethers(PVEs), and polycarbonates (PCs).

Lubricants are selected by considering a given compressor's requirementsand the environment to which the lubricant will be exposed.

Of note are high temperature lubricants with stability at hightemperatures. The highest temperature the heat pump will achieve willdetermine which lubricants are required. In one embodiment, thelubricant must be stable at temperatures of at least 55° C. In anotherembodiment, the lubricant must be stable at temperatures of at least 75°C. In another embodiment, the lubricant must be stable at temperaturesof at least 100° C. In another embodiment, the lubricant must be stableat temperatures of at least 139° C. In another embodiment, the lubricantmust be stable at temperatures of at least 145° C. In anotherembodiment, the lubricant must be stable at temperatures of at least155° C. In another embodiment, the lubricant must be stable attemperatures of at least 165° C. In another embodiment the lubricantmust be stable at temperatures of at least 170° C. In another embodimentthe lubricant must be stable at temperatures of at least 200° C. Inanother embodiment the lubricant must be stable at temperatures of atleast 250° C.

Of particular note are poly alpha olefin (POA) lubricants with stabilityup to about 200° C. and polyol ester (POE) lubricants with stability attemperatures up to about 200 to 220° C. Also of particular note areperfluoropolyether (PFPE) lubricants that have stability at temperaturesfrom about 220 to about 350° C. PFPE lubricants include those availablefrom DuPont (Wilmington, Del.) under the trademark Krytox®, such as theXHT series with thermal stability up to about 300 to 350° C. Other PFPElubricants include those sold under the trademark Demnum™ from DaikinIndustries (Japan) with thermal stability up to about 280 to 330° C.,and available from Ausimont (Milan, Italy), under the trademarksFomblin® and Galden® such as that available under the trademarkFomblin®-Y Fomblin®-Z with thermal stability up to about 220 to 260° C.

For high temperature condenser operation (associated with hightemperature lifts and high compressor discharge temperatures)formulations of working fluid (e.g. HFO-153-10mzzy) and lubricants withhigh thermal stability (optionally in combination with oil cooling orother mitigation approaches) will be advantageous.

In one embodiment, the compositions may further comprise from about 0.01weight percent to about 5 weight percent of a stabilizer, (e.g., a freeradical scavenger, an acid scavenger or an antioxidant) to preventdegradation caused at high temperatures. Such other additives includebut are not limited to, nitromethane, hindered phenols, hydroxylamines,thiols, phosphites, or lactones. Of note are compositions wherein thecompositions comprise from about 0.1 weight percent to about 3 weightpercent of a stabilizer. Single stabilizers or combinations may be used.

Optionally, in another embodiment, certain refrigeration,air-conditioning, or heat pump system additives may be added, asdesired, to the working fluids as disclosed herein in order to enhanceperformance and system stability. These additives are known in the fieldof refrigeration and air-conditioning, and include, but are not limitedto, anti-wear agents, extreme pressure lubricants, corrosion andoxidation inhibitors, metal surface deactivators, free radicalscavengers, and foam control agents. In general, these additives may bepresent in the working fluids in small amounts relative to the overallcomposition. Typically concentrations of from less than about 0.1 weightpercent to as much as about 3 weight percent of each additive are used.These additives are selected on the basis of the individual systemrequirements. These additives include members of the triaryl phosphatefamily of EP (extreme pressure) lubricity additives, such as butylatedtriphenyl phosphates (BTPP), or other alkylated triaryl phosphateesters, e.g. Syn-O-Ad 8478 from Akzo Chemicals, tricresyl phosphates andrelated compounds. Additionally, the metal dialkyl dithiophosphates(e.g., zinc dialkyl dithiophosphate (or ZDDP); Lubrizol 1375 and othermembers of this family of chemicals may be used in compositions of thepresent invention. Other antiwear additives include natural product oilsand asymmetrical polyhydroxyl lubrication additives, such as SynergolTMS (International Lubricants). Similarly, stabilizers such asantioxidants, free radical scavengers, and water scavengers may beemployed. Compounds in this category can include, but are not limitedto, butylated hydroxy toluene (BHT), epoxides, and mixtures thereof.Corrosion inhibitors include dodecyl succinic acid (DDSA), aminephosphate (AP), oleoyl sarcosine, imidazone derivatives and substitutedsulfphonates. Metal surface deactivators include areoxalylbis(benzylidene) hydrazide (CAS reg no. 6629-10-3),N,N′-bis(3,5-di-tert-butyl-4-hydroxyhydrocinnamoylhydrazine (CAS reg no.32687-78-8),2,2,′-oxamidobis-ethyl-(3,5-di-tert-butyl-4-hydroxyhydrocinnamate (CASreg no. 70331-94-1), N,N′-(disalicyclidene)-1,2-diaminopropane (CAS regno. 94-91-7) and ethylenediaminetetra-acetic acid (CAS reg no. 60-00-4)and its salts, and mixtures thereof.

Of note are stabilizers to prevent degradation at temperatures of 55° C.or above. Also of note are stabilizers to prevent degradation attemperatures of 75° C. or above. Also of note are stabilizers to preventdegradation at temperatures of 85° C. or above. Also of note arestabilizers to prevent degradation at temperatures of 100° C. or above.Also of note are stabilizers to prevent degradation at temperatures of139° C. or above. Also of note are stabilizers to prevent degradation attemperatures of 145° C. or above. Also of note are stabilizers toprevent degradation at temperatures of 155° C. or above. Also of noteare stabilizers to prevent degradation at temperatures of 165° C. orabove. Also of note are stabilizers to prevent degradation attemperatures of 170° C. or above. Also of note are stabilizers toprevent degradation at temperatures of 200° C. or above. Also of noteare stabilizers to prevent degradation at temperatures of 250° C. orabove.

Of note are stabilizers comprising at least one compound selected fromthe group consisting of hindered phenols, thiophosphates, butylatedtriphenylphosphorothionates, organo phosphates, or phosphites, arylalkyl ethers, terpenes, terpenoids, epoxides, fluorinated epoxides,oxetanes, ascorbic acid, thiols, lactones, thioethers, amines,nitromethane, alkylsilanes, benzophenone derivatives, aryl sulfides,divinyl terephthalic acid, diphenyl terephthalic acid, ionic liquids,and mixtures thereof. Representative stabilizer compounds include butare not limited to tocopherol; hydroquinone; t-butyl hydroquinone;monothiophosphates; and dithiophosphates, commercially available fromCiba Specialty Chemicals, Basel, Switzerland, hereinafter “Ciba,” underthe trademark Irgalube® 63; dialkylthiophosphate esters, commerciallyavailable from Ciba under the trademarks Irgalube® 353 and Irgalube®350, respectively; butylated triphenylphosphorothionates, commerciallyavailable from Ciba under the trademark Irgalube® 232; amine phosphates,commercially available from Ciba under the trademark Irgalube® 349(Ciba); hindered phosphites, commercially available from Ciba asIrgafos® 168; a phosphate such as (Tris-(di-tert-butylphenyl),commercially available from Ciba under the trademark Irgafos® OPH;(Di-n-octyl phosphite); and iso-decyl diphenyl phosphite, commerciallyavailable from Ciba under the trademark Irgafos® DDPP; anisole;1,4-dimethoxybenzene; 1,4-diethoxybenzene; 1,3,5-trimethoxybenzene;d-limonene; retinal; pinene; menthol; Vitamin A; terpinene; dipentene;lycopene; beta carotene; bornane; 1,2-propylene oxide; 1,2-butyleneoxide; n-butyl glycidyl ether; trifluoromethyloxirane;1,1-bis(trifluoromethyl)oxirane; 3-ethyl-3-hydroxymethyl-oxetane, suchas OXT-101 (Toagosei Co., Ltd); 3-ethyl-3-((phenoxy)methyl)-oxetane,such as OXT-211 (Toagosei Co., Ltd);3-ethyl-3-((2-ethyl-hexyloxy)methyl)-oxetane, such as OXT-212 (ToagoseiCo., Ltd); ascorbic acid; methanethiol (methyl mercaptan); ethanethiol(ethyl mercaptan); Coenzyme A; dimercaptosuccinic acid (DMSA);grapefruit mercaptan ((R)-2-(4-methylcyclohex-3-enyl)propane-2-thiol));cysteine ((R)-2-amino-3-sulfanyl-propanoic acid); lipoamide(1,2-dithiolane-3-pentanamide); 5,7-bis(1,1-dimethylethyl)-3-[2,3 (or3,4)-dimethylphenyl]-2(3H)-benzofuranone, commercially available fromCiba under the trademark Irganox® HP-136; benzyl phenyl sulfide;diphenyl sulfide; diisopropylamine; dioctadecyl 3,3′-thiodipropionate,commercially available from Ciba under the trademark Irganox® PS 802(Ciba); didodecyl 3,3′-thiopropionate, commercially available from Cibaunder the trademark Irganox® PS 800;di-(2,2,6,6-tetramethyl-4-piperidyl)sebacate, commercially availablefrom Ciba under the trademark Tinuvin® 770;poly-(N-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxy-piperidyl succinate,commercially available from Ciba under the trademark Tinuvin® 622LD(Ciba); methyl bis tallow amine; bis tallow amine;phenol-alpha-naphthylamine; bis(dimethylamino)methylsilane (DMAMS);tris(trimethylsilyl)silane (TTMSS); vinyltriethoxysilane;vinyltrimethoxysilane; 2,5-difluorobenzophenone;2′,5′-dihydroxyacetophenone; 2-aminobenzophenone; 2-chlorobenzophenone;benzyl phenyl sulfide; diphenyl sulfide; dibenzyl sulfide; ionicliquids; and others.

Also of note are ionic liquid stabilizers comprising at least one ionicliquid. Ionic liquids are organic salts that are liquid or have meltingpoints below 100° C. In another embodiment, ionic liquid stabilizerscomprise salts containing cations selected from the group consisting ofpyridinium, pyridazinium, pyrimidinium, pyrazinium, imidazolium,pyrazolium, thiazolium, oxazolium and triazolium; and anions selectedfrom the group consisting of [BF.sub.4]-, [PF.sub.6]-, [SbF.sub.6]-,[CF.sub.3SO.sub.3]--, [HCF.sub.2CF.sub.2SO.sub.3]-,[CF.sub.3HFCCF.sub.2SO.sub.3]-, [HCCIFCF.sub.2SO.sub.3]-,[(CF.sub.3SO.sub.2).sub.2N]—, [(CF.sub.3CF.sub.2SO.sub.2).sub.2N]—,[(CF.sub.3SO.sub.2).sub.3C]—, [CF.sub.3CO.sub.2]-, and F—.Representative ionic liquid stabilizers include emim BF.sub.4(1-ethyl-3-methylimidazolium tetrafluoroborate); bmim BF.sub.4(1-butyl-3-methylimidazolium tetraborate); emim PF.sub.6(1-ethyl-3-methylimidazolium hexafluorophosphate); and bmim PF.sub.6(1-butyl-3-methylimidazolium hexafluorophosphate), all of which areavailable from Fluka (Sigma-Aldrich).

EXAMPLES

The concepts described herein will be further described in the followingexamples, which do not limit the scope of the invention described in theclaims.

Example 1 Chemical Stability of HFO-153-10Mzzy at High Temperatures

The thermal stability of HFO-153-10mzzy was assessed through testing insealed glass tubes according to the methodology of ANSI/ASHRAE Standard97-2007. Samples of HFO-153-10mzzy were placed in glass tubes withimmersed coupons of metals (Fe, Al, Cu, Stainless Steel 304) commonlyused in the construction of heat pumps and other equipment. The tubeswere sealed and heated in an oven at 175° C. for 32 days. Thedecomposition of HFO-153-10mzzy after aging for 32 days was quantifiedin terms of the measured fluoride ion concentration in parts per million(ppm). The concentration of fluoride ion resulting from the degradationof HFO-153-10mzzy was less than 100 ppm indicating good thermalstability. HFO-153-10mzzy, despite its unsaturated chemical nature,exhibited thermal stability similar to Novec® HFE-7100, as shown inTable 1 below.

TABLE 1 Metal/Catalyst HFO-153-10mzzy Novec ® HFE-7100 Fe 4.3 1.0 Al 2.06.8 Cu 1.3 4.5 Stainless Steel 304 5.1 6.1

High thermal stability, non-flammability, low GWP, high criticaltemperature and low vapor pressure make HFO-153-10mzzy attractive as aworking fluid in high temperature heat pumps.

Example 2 Heat Pump Performance with HFO-153 10Mzzy for Lifting Heatfrom 80° C. to 126° C.

Table 2 shows the performance data of a heat pump used to lift heat from80° C. to 126° C. operating with HFO-153-10mzzy as the working fluid ascompared to the performance data of a heat pump operationing withHFC-245fa as the working fluid. In addition to offering a significantlylower GWP, HFO-153-10mzzy realizes a 4.1% higher CORI. Moreover, thecompressor discharge temperature with HFO-153-10mzzy is within the upperlimit for most compressors while the compressor discharge temperaturewith HFC-245fa exceeds the upper limit for most compressors.

TABLE 2 HFO-153 10mzzy vs. HFC- HFC- 245fa 245fa HFO-153 10mzzy % T_(cr)° C. 154 170.24 P_(cr) MPa 3.65 2.04 T_(b) ° C. 15.1 49 T_(evap) ° C. 8080 T_(cond) ° C. 126 126 Lift ° C. 46 46 Suction Superheat K 25 25Liquid K 15 15 Subcooling Compressor 0.7 0.7 Efficiency P_(cond) MPa2.17 0.84 T_(disch) ° C. 146.12 130.64 COP_(h) 5.644 5.875 +4.1

Example 3 Heat Pump Performance with HFO-153 10Mzzy for Lifting Heatfrom 90° C. to 145° C.

Table 3 shows the performance data of a heat pump used to lift heat from90° C. to 145° C. operating with HFO-153-10mzzy as the working fluid ascompared to the performance data of a heat pump used to lift heat from90° C. to 126° C. operating with HFC-245fa as the working fluid. Themaximum permissible working pressure for many heat pumps (e.g. commonlyavailable centrifugal heat pumps) is about 2.18 MPa; it limits thecondensing temperature with HFC-245fa to a maximum of about 126° C. Thecondensing pressure for the heat pump operated with HFO-153-10mzzy asthe working fluid remains comfortably below the maximum permissibleworking pressure of 2.18 MPa even at the higher condensing temperatureof 145° C. Moreover, the compressor discharge temperature withHFO-153-10mzzy remains below that with HFC-245fa even with thesignificantly higher temperature lift with HFO-153-10mzzy. Therefore, inaddition to offering a significantly lower GWP than HFC-245fa,HFO-153-10mzzy could enable the realization of heat pumps achievinghigher heating temperatures than HFC-245fa. It could also enable theretrofit of heat pumps originally design for HFC-245fa, so as to reducethe GWP of the working fluid while at the same time allowing higherheating temperatures.

TABLE 3 HFC- HFO-153 245fa 10mzzy T_(evap) ° C. 90 90 T_(cond) ° C. 126145 Lift ° C. 36 55 Suction Superheat K 35 35 Liquid Subcooling K 15 15Compressor 0.7 0.7 Efficiency P_(cond) MPa 2.17 1.26 T_(disch) ° C.156.78 155.93 COP_(h) 7.656 4.951

What is claimed is:
 1. A method for producing heating in a hightemperature heat pump apparatus having a heat exchanger comprisingextracting heat from a working fluid, thereby producing a cooled workingfluid wherein said working fluid comprises(2E)-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)pent-2-ene, whereinthe heat exchanger operates at a temperature of at least about 55° C. 2.The method of claim 1 wherein the heat exchanger is selected from thegroup consisting of a supercritical working fluid cooler and acondenser.
 3. The method of claim 1 further comprising passing a firstheat transfer medium through the heat exchanger, whereby said extractionof heat heats the first heat transfer medium, and passing the heatedfirst heat transfer medium from the heat exchanger to a body to beheated.
 4. The method of claim 3, wherein the first heat transfer mediumis an industrial heat transfer liquid and the body to be heated is achemical process stream.
 5. The method of claim 1 further comprisingexpanding the working fluid and then heating the working fluid in asecond heat exchanger to produce a heated working fluid.
 6. The methodof claim 3 wherein said second heat exchanger is an evaporator and theheated working fluid is a vapor.
 7. The method of claim 4, furthercomprising compressing the working fluid vapor in a dynamic or apositive displacement compressor.
 8. The method of claim 5, wherein thedynamic compressor is a centrifugal compressor.
 9. The method of claim 1further comprising passing a fluid to be heated through said heatexchanger, thus heating the fluid.
 10. The method of claim 1, whereinthe high temperature heat pump apparatus is suitable for use withHFC-245fa.
 11. A method of raising the maximum feasible condenseroperating temperature to a temperature greater than about 127° C. in ahigh temperature heat pump apparatus comprising: charging the hightemperature heat pump apparatus with a working fluid comprising(2E)-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)pent-2-ene.
 12. Themethod of claim 11, wherein the high temperature heat pump apparatus issuitable for use with HFC-245fa.
 13. The method of claim 1, wherein theheat exchanger operates at a temperature of at least about 127° C. 14.The method of claim 1, wherein the heat exchanger operates at atemperature of at least about 155° C.
 15. The method of claim 1, whereinthe heat exchanger operates at a temperature from about 160° C. to about169° C.
 16. The method of claim 11 wherein the maximum feasiblecondenser operating temperature is raised to a temperature greater thanabout 155° C.
 17. The method of claim 11 wherein the maximum feasiblecondenser operating temperature is raised to a temperature greater thanabout 160° C.
 18. The method of claim 11 wherein the maximum feasiblecondenser operating temperature is raised to a temperature greater thanabout 168° C.